Electric selector



1934- H. E. HUMPHRIES 1,970,455

ELECTRIC SELECTOR Filed April 26, 1930 5 Sheets-Sheet l 1 Fig M IZZVENTORI w z. W

HTTORN E Y Aug. 14, 1934.

H. E. HUMPHRIES 1,970,455

- ELECTRIC SELECTOR Filed April 26. 1950 5 Sheets-Sheet 2 Fig. 5. J/fUA/T F761 0 EELA Y ATTORNQ/ 1934- H. E. HUMPHRIES 1,970,455

4 ELECTRI C SELECTOR Filed April 26, 1950 5 Sheets-Sheet 3 Fig. 6.

7 34.1. @LZLM Aug. 14, 1934. H. E. HUMPHRIES ELECTRI C SELECTOR Filed April 26, 1930 5 Sheets-Sheet 4 m/v/rwa mam-r G/VET MO/FJE S/GWAL AEcoeaqa Aug. 14, 1934. H. E. HUMPHRIES ELECTRIC SELECTOR Filed April 26. 19:50

5 Sheets-Sheet 5 INVENTOR @w a z. fl/M ATTORNEY Patented Aug. 14, 1934 ELECTRIC SELECTOR Horace Edgar Humphries, London, England, as-

signor to Siemens Brothers at 00., Limited, London, England, a British company Application April 26, 1930, Serial No. 447,636 In Great iiiritain April 29, 1929 4 Claims.

This invention relates to electric selectors and more particularly to electric selectors operable by impulses of prescribed duration separated by breaks of prescribed duration.

Such selectors may be used, for example, in Wireless telegraph systems to establish that an alarm signal is being received and to give thereupon an audible or visual signal or both.

The resent wireless alarm signal laid down for marine purposes requires a sequence of three marks of four seconds each, separated by spaces of one second each. To meet the case that the timing or" the signals in sending may be faulty, a tolerance is nevertheless permitted and the signals should be accepted provided a marking period is not less than 3 seconds and not more than 4 seconds and a space period is not less than second and not more than 1%; seconds. The selector of the present invention is adapted to take into consideration such tolerances and will accept a mark as being permissible if it lies between the limits of 3 and 4 seconds and a space if it lies between second and 1% seconds.

' For the timing of marks and spaces, the timing devices hitherto used have comprised cams which are coupled as required to constantly rotating members and which operate on contacts after a certain period of drive and relays provided with dashpots to the end that contacts are operated or released after a period of delay.

it extremely desirable that any timing device used should be capable of very rapid restoration to normal after having timed an event, so as to be ready to time a succeeding event. A pendulum timing device would not fulfil these requirements by reason of its inherent momentum.

The present invention includes an improved form of timing device that can be re-set very rapidly to normal. The fundamental feature of the timing device is that it includes a periodically operated relay which is held operated temporarily by the discharge from a condenser. The relay may interrupt its own circuit on operating but 5 preferably an additional relay is used to cause an interaction. To render the size of the condenser reasonable, the time of periodic operation of the relay is a lowed to be small compared with the period to be measured and the operations of the relays are recorded. It is convenient to make the period of the operating cycle of the relay some sub-multiple of the periods to be measured, for instance, one half second.

It is very desirable for manufacturing and operating purposes that the effect of variation in the air gap of the relay and variations of the load on the relay springs on the time of periodic operation should be diminished as far as possible. With this object in view, we arranged that the condenser whilst timing is taking place is steadily connected in parallel with the relay winding and the source of current for operating the relay is connected through a high impedance choke to the relay. If a relay is actually caused to operate the discharge of a condenser and in due course eleases as the discharge falls off, a variation of the relay air gap and/or the spring load has a very marked eifect on the time the relay is operated, an increase in either of these factors resulting in a decrease of the operating time and vice versa.

The inclusion of the choke and the steady con nection oi" the condenser has the effect that an increase of air gap or spring load delays the operation of the relay but allows of earlier release and vice versa so that the operating cycle is approximately constant for variations that may be expected in practice or occur from time to time. A resistance in place of a choke whilst not being so effective in this compensating action might conveniently be used.

To provide for the rapid restoration of the relay to normal when a timing operation ceases, the condenser is disconnected and discharged through a suitable resistance so that only the release lag of the relay, which is small, is concerned.

For recording the cycles of operation that take place whilst a signal is being timed a cycle recording device is provided and we prefer to use a or relays which are controlled by the timing device. These relays are conveniently arranged in pairs, a pair executing a cycle of operation and release under the influence of control contacts. It can easily be arranged that a pair of relays executes one cycle for every two cycles of the preceding pair or in the case of the first pair, two cycles oi the timing device.

The relay set establishes whether a mark has endured a time within the permissible limits, and if not, may prepare to close a circuit for immediate restoration. In the case of a jamming signal, we prefer to delay restoration of the selecting apparatus to normal until the signal ceases so that there is no possibility that a portion of the jamming signal is accepted as a permissible mark.

Beyond the cycle recorder the selecting apparatus includes a device for recording the receipt of permissible marks and when three such marks in the case of a marine alarm signal have been received, an alarm circuit is closed.

We prefer again to employ relays for this pur pose so that the complete apparatus can consist of relays.

Spaces may be timed by the timing device and cycle recorder and thereby it may be ascertained that a space does not exceed the permissible amount. On the other hand we may provide a separate timing device for spaces as will be hereinafter set out. That a space endures one fifth of a second in practice means only that some space has occurred between two marks, and no ascertainment is made of the actual duration beyond ascertaining that it does not exceed the prescribed limit, it being considered that the time taken for relays to release, settles that a space has, at all events, taken place. Space timing only takes place if a prescribed mark has been received as in certain prior forms of selecting devices.

The accompanying drawings will be referred to for the better carrying out of the invention. Fig. 1 illustrates a general form of the timing device for the periodic opening and closing of a circuit; Fig. 2 shows a control relay associated with the timing device; and Fig. 3 means for starting the timing device; Fig. 4 a portion of a cycle recording device. Fig. 5 shows selecting apparatus suitable for wireless alarm purposes. Fig. 6 a diagram for the better explanation of the operation of the apparatus in Fig. 5.

Further selecting apparatus is shown in Figs. '7 and 9 and Fig. 8 is explanatory of Fig. '7.

In the accompanying drawings the relays are each designated by a capital letter and each contact thereof by numerals. In the subsequent description each relay operating coil is referred to by the capital letter designating the relay, whilst to render the description concise and lucid each contact of the relay referred to by its numeral prefixed by a small letter of the capital designating the relay, for example, referring to Fig. 1, relay Z has an operating coil to be designated Z and two contacts referred to as el and 22.

The relays and circuits in the figures are served from a common battery with the exception of the anode circuits of the thermionic tubes, such as V4 Figs. 5, 7 and!) and in Figs. 5, 7 and 9 to avoid complication coils or contacts connected to positive or negative battery are marked by a or sign respectively, and it is to be understood that these connections lead to the marked common leads connected to the battery.

Referring to Fig. 1 relay Z has shunted across it a condenser QA, and in series with the paralleled relay and condenser is a choke W and contacts 1/1 of a control relay Y. When the battery is connected relay Y operates in a circuit from positive battery, contacts 21, coil of relay Y to negative battery. On the closure of contacts 111 the condenser QA charges up gradually by reason of the choke W, and the condenser in its uncharged state provides a shunt across the coil of relay Z and prevents its energization. The voltage across the condenser rises and the current in the coil of relay Z increases until the current is sufficient to operate the relay. When relay Z operates the operating circuit for relay Y is opened at contacts 21. When relay Y releases the circuit for the coil of relay Z is opened, but relay Z does not release at once as condenser QA discharges and maintains the relay operated for a short period. When relay Z releases the circuit for the coil of relay Y is again closed at contacts .21 and relay Y re-operates and the cycle is repeated. Contacts 22 at each operation, or it may be release, of relay Z, close the circuit which is to be periodically opened or closed.

Whilst it is possible to cause relay Z to interrupt its own circuit when operated, and thus cause its periodic operation and release, it is preferable to cause the interruption by using an auxiliary relay which can then be provided with contacts to control the circuits which are to be periodically opened and closed, and the function of relay Z, which is timing, is not subject to the influence of spring sets additional to those required for the auxiliary relay. I

Fig. 2 shows one way in which an auxiliary relay may be associated with relay Z. Condenser QC and resistance YB shunted across relay Y serve to quench sparks at contact 21. Condenser QB is also for spark quenching. The variable resistance YA is for the purpose of adjusting the frequency of beat of the relay combination; the greater the resistance inserted by YA the less is the frequency.

The operation of the relay combination is as follows:--On the closure of contacts 21, that is when relay Z releases or when the operating battery is connected, a circuit is closed for relay Y from positive battery, coil of relay Y, contacts 21, to negative battery. Relay Y operates and at contacts 1/1 a control circuit is made for relay Z from positive battery, variable resistance YA, coil of relay Z, choke W in parallel with condenser QB, to negative battery. The choke W and condenser QB particularly the former delay the rise of voltage across relay Z but in due course the voltage across the relay rises to a value suiiicient to cause its operation. On the operation of relay Z contacts 21 open the previously traced circuit for relay Y at contacts yl. The relay Z however does not release immediately by reason of the charge in condenser QA dissipating itself through the relay and the variable resistance YA, the rate of discharge depending on the adjustment of resistance YA. When relay Z ultimately releases the previously traced circuit for relay Y is reestablished and relay Y reoperates to recommence the cycle of operations.

As a guide to the characteristics of the relay combination, a combination having the following characteristics gave a beat period of approximately one half second:-

Relay Z10,000 ohms resistance (D. (1.).

Relay U-1,000 ohms resistance (D. C.).

Iron cored choke-3,000 ohms resistance (D. C.).

Capacity of QA-15 microfarads.

The relays were of the telephone type and the choke of the type known as an output choke in wireless receiving apparatus.

Condenser QB 0.1 microfarad. The spark quench YB and QC was made up by a 1 microfarad condenser and a ten ohm resistance: supply voltage 100.

In Fig. 3 a control relay X is shown which relay lowing circuit for relay Y is completed, positive battery, coil of relay Y, contacts zl, contacts $2 to negative battery.

Relay Y operates and a circuit for relay Z is closed from positive battery, variable resistance YA, and coil of relay Z, the condenser QA being in parallel with this series circuit over contacts 331, choke W, the condenser QB being in parallel therewith, contacts yl to negative battery. The potential rise across relay Z is delayed directly by the condenser QA, whilst the potential rise in the whole of the circuit is delayed by the choke 'W.

Thus relay Z will not operate until the potenial across the relay rise above a predetermined value, the relay being thus delayed in operation. When relay Z operates, the previously traced circuits for the coils of relays I; and Y are opened at contacts .22 and 21 respectively, the relays releasing at the same time. With the release of relay Y the previously traced circuit for relay Z is opened at contacts 111, the release of contacts cs1 disconnectin the condenser QA from across relay Z and connecting it to resistance Y through which resistance the charge the condenser is quickly dissipated. By the removal of condenser QA from across relay Z the r lay is allowed to release quickly. When relay Z releases the above traced circuit for relay X is again closed over contacts 22 and the cycle of operations is repeated. The operating lag given to relay Z is adjustable by the variation of. resistance YA.

It will be appreciated by those skilled in art that the auxiliary relay Y might be released by a difierential winding the circuit of which is closed by a contact of relay Z when this relay operates.

For the recording of the number of beats or cyclical operations of the relays Y and Z, te multiplying relay combinations shown in 4 may be made use of. It comprises a pair or relays A and B each provided with two windings, and the pair is controlled by contacts g2 of a relay Y as shown in Fig. 3.

It should be understood that Figs. 1, 2, 3, illustrate only a limited number of circuit arrangements for the control of the timing devices, and that many modifications will suggest themselves to those versed in the art, for example, the control of the beat frequency may be provided for by the use of a variable condenser or by the variable resistance in series with the choke.

0n the first closure of contacts g2, relay A is operated over its coil 1 in a circuit from positive battery, contacts b2, coil 1 of A, contacts bl and y2 to negative. Relay A operates and at contacts (12 prepares a further circuit for itself. At contacts a1 a circuit is closed for coil 1 of re lay B but the relay does not operate as the coil is yet short-circuited over contacts g2. 0n contacts 1/2 opening relay B operates over its coil 1 in series with coil 1 of relay A. Contacts 111 change over without effect at this stage. On the next closure of contacts 112 a holding circuit for relay B is made over its coil II and contacts bl and g2. Current also flows through coil II of relay A, which coil is differential and opposes coil I. Relay A is consequently de-magnetized and releases, opening thereby its contacts a1 and a2 so that it stays released. When contacts g2 open, the holding circuit of relay B is opened and it releases. The next re-closure of contacts 112 cause the sequence of operations described, to be repeated.

It will be now clear that two complete operations of relay Y result in the operation of relay A, operation of B, release of A and release of B. The combination of relays A and B therefore, execute a complete cycle for every two cycles of relay Y. By means of control contacts a1 and b3 a further combination of relays may be controlled in the same manner as contacts g2 control relays A and B, the cyclical period of the further combination being double that of the relay pair A and B.

The explanation of the use of a pair of relays for giving a cyclical period which is double that of the period of a controlling contact is given here to lessen the explanations necessary in connection with the alarm device yet to be described.

Fig. 5 shows one form of selecting apparatus suitable -lZor wireless alarm purposes. In Fig. 5 the alarm circuit is closed by a relay L.

The last valve V of receiving apparatus is shown on the left and its plate or anode is connected to the positive terminal of a high tension supply HT through a relay S. The grid potential of the valve is normally sufficiently positive to allow sufficient current to flow to the plate so that relay S is maintained operated. It is arranged in known manner that sufiiciently strong incoming signal causes the grid to a"- sume negative potential whereby relay S releases and is only re-operated when the signal ceases.

Relays P and N are filament supply alarm relays of the consequent pole type, that is comprising two coils each one embracing an arm of a core forming a closed magnetic system it being necessary to energize both coils to produce simi-- lar magnetic effects in both arms before the armature is attracted. The circuit for each filament of the tubes such as V passes through the filament and one coil of a relay such as P or N and thence to on side of the common battery and thence from a tapping off the common battery back to the filament. Thus one relay will serve two filaments and providing that both filament circuits are continuous a current will pass through both coils of the relay and it will remain operated. However if the current in one or both coils of the relay ceases indicating a discontinuance of the filament current, the relay will release and at its contacts, such as pi and 12.1 or both, close an obvious circuit for relay L which latter relay at its contacts contacts Z2 will close an obvious circuit for alarm bell AB, and at con-- tacts Z3 close an obvious circuit for magnet SM hereinafter referred to. Obviously a separate alarm relay might be used instead of using relay L.

The relays A to F form the cycle recording device relays J, H and K the sequence recording device. Relay M is operated when a mark is of the prescribed duration. Relay R serves to restore the apparatus to normal. Relays Y and Z form the timing device. Other parts will be referred to in the course of the following description. It will be assumed that the cyclical period of the relay pair Z and Y has been adjusted to one half second by means of the resistance YA.

If an alarm signal commences relay 5 releases on the first mark commencing. A circuit is then made from positive battery over contacts and s1, coil of relay SA to negative battery, and the relay SA operates. Contacts $0.2 open without efiect at this stage and at contacts cal a circuit is made from positive battery over guard resistance YD, contacts Z1 and sal, coil I of relay X to negative battery. Relay X operates and at 115g contacts m1 disconnects the resistance YC from across condenser QA, and connects the condenser QA across the series connection of relay Z and resistance YA. A circuit for relay Y is completed from positive battery, relay Y, contacts 21 contacts $2 to negative battery. At contacts $3 a circuit is prepared for relays A, B--G, as hereinafter described.

Relay Y operates and completes a circuit for relay Z from positive battery HT, resistance YA, coil of relay Z, contacts /1, choke W, to negative battery HT, the condenser QA being connected in parallel with the relay Z and resistance YA over a circuit from positive battery HT and one side of resistance YA, condenser QA, contacts 2' to one side of relay Z. Relay Z however owing to the choke W and the condenser QA does not op-- erate immediately. A circuit is made for coil I of relay A from positive battery contacts b2, coil I of relay A, contacts b1, contacts y2 and $3, to negative battery. Comparison with Fig. 4 will show that the circuit arrangements of the relays A and B are the same as in that figure.

Relay A operates and locks itself by positive battery over contac :5 a2, independent of contacts 122 to the negative battery on contacts m3 as previously traced.

At contacts a1 a circuit is prepared for coil I of relay B but this relay cannot operate as it is short circuited as follows:-upper side of coil I of relay B, contacts 131, 1 2, contacts al, to the bottom side of coil I of relay B. It will be seen that contacts (13 are connected in parallel with contacts b4, 04, c4 and g5 the purpose of. W11 11 will be hereinafter explained. Contacts as prepare to operate the buzzer BZ under conditions hereinafter referred to, whereas contacts a5 prepare the circuit for relay U, this circuit remaining open until relay G operates its contacts g6 as will be subsequently described.

The operation of relay Z is delayed by the choke W and condenser QA, but in due course it operates and at contacts .21 opens the previously traced circuit for relay Y which releases and at contacts yl opens the circuit for relay Z.

; ferred to. Contacts b3 prepare a circuit for relays C and D. Contacts bl disconnect the original operating circuit for relay A and prepare for its release.

If the first mark persists after the relays A and B have operated relay X remains operated, and therefore when relay Z releases the circuit for relay Y is again closed overcontacts 22 and 21 as previously described. Relay Y closes the circuit for relay Z over contacts g1.

When relay Y again operates a negative battery is connected over contacts :03, g2, bl coil II of relay A, contacts a2 to positive battery. Relay B locks in parallel with coil II of relay A. The coil II of relay A is connected differentially to coil I and the energization of the forrnercoil causes the relay to release. Relay A therefore releases and in doing so closes the following circuit positive battery contacts d2, coil I of relay Qcontacts d1, b3, a1 and $3 to negative battery. Relay C theretore operates and at contacts 03 prepares theopcrating circuit for relay D over its coil I. Relay D cannot operate owing to the short circuit across its coil I over contacts d1, b3, a1 and c1. The relay C locks over its coil I and coil I of relay D, contacts 01 and 11:3 to negative battery.

When relay Y releases upon relay Z operating the negative battery holding relay B from contacts 0:3 is disconnected at contacts 112 and relay B releases. The relay B in releasing opens the previously traced short circuit across coil I of relay D and this relay operates from negative battery, contacts :03. contacts 01, coils I of relay D and C, contacts c2 to positive battery, and looks over this circuit.

If the mark still persists on the next operation of relay Y relay A is again operated followed by relay B, when relay Y releases, in the manner previously described. When relay A releases on the next operation of relay Y relay C is released by the energization of its coil II over the following circuit, negative battery contacts 333, a1, b3, d1, coil II of relay 0, contacts 02 to positive battery. Relay C releases whilst relay B is held from negative battery over contacts 923, g2, b1 coil II of relay B, to positive battery, and relay D from negative battery over contacts .13, a1, b3, d1, coil II of relay D, to positive battery. When relay Y releases on the operation of relay Z the holding circuit for relay B is opened at contacts 2 and relay B releases opening at contacts b3 the holding circuit for relay D.

Before relay D releases however the following circuit for relay E is completed from negative battery contacts cl, d3, fl, coil I of relay E, contacts to positive batte y. Relay E operates and looks over its contacts 62, coil I of relay E, coil I of relay I contacts c1, and Relay Fcannot operate over its coil I as this coil is short circuited at this time over contacts e1, 01, dB, and f1. However when relay 1) falls back as previously described the short circuit is removed from call I of relay F at contacts; (13, and relay F operates and locks in series with coil I of relay E to the contacts will now be understood.

When relay Y again operates relay A operates as previously dcsc ibed and on the release of relay Y relay B operates. On the next operation of relay Y relay A releases followed by the operation of relay C, relay B relea.-" 1g on release of relay Y allowing the operation of relay D. When relay Y again. operates relay A operates followed by re lay B on the release of relay Y. When relay Y reoperates relay A role and causes the release of relay C. Relay C in releasing closes the following circuit for coil. II of relay E, negative battery con- 1 tacts cl, d3. 1'1, coil Iii oi relay E, contacts e2 to positive. Relay E t ,re'iorc releases and closes a circuit for coil II of relay G l'rom positive battery, coil II of relay contacts T3, 13, e1, 2:3 to

negative battery. Relay G operates and looks over I ated after seven cycles of the Z-Y relay coinbij nation, and if each cycle occupies one half second, three and one half seconds elapse before relay G operates as clearly shown.

The indications first, second and so on at the top of the chart indicate theends of half seconds heretofore elapsing from the commencement of cyclical operation of relay Y. It will be seen that the first release of relay 13 takes place the second time that relay Y releases as pointed out in connection with Fig. 4; also that relay C of a pair C and D is first operated when relay A is released whilst relay B operated.

When 3 /2 seconds have elapsed from the setting into operation of relay Y, that is to say, the lower limit of durationoi a permissible marl; has been received, relay Y has completed its seventh. cycle. Relays B, D and F are operated and relays A, C and E are on the point of releasing.

When relay E releases which occurs on the next operation of relay Y, a circuit made for relay Ci over back contacts 21 and front contacts f3. Re lay G locks up over contacts g1.

RelayG on operating at contacts o3 closes an obvious circuit for relay M, whereas at contacts g2 a circuit is closed for coil I of relay H from positive battery, contacts 9'2, coil I of relay l i, contacts l, 92, T1, to negative battery. Relay H locks over its contacts 712 and relay J is prepared to operate over its coil I and contacts hl as will now be understood.

Assume that the mark signal ceases before the maximum duration allowable, which is 4 seconds, is exceeded. It should be noted that just before 4 seconds have elapsed, the relays A to F are all at normal, as shown by Fig. 6 and the set starts once more into cyclical operation at the commencement of the fifth second.

Relay G operates when 3 seconds have elapsed and this relay in combination with relay C which operates once more a second later in the manner described, determines whether the maximum of the permissible mark has been exceeded. The mark signal having ceased as mentioned the grid of the tube V assumes positive potential and relay S re-operates with the result that relay SA releases due to the opening of cntacts sl. Since contact m2 closed a circuit is made for coil II of relay X from positive battery, resistance YD, contacts ll, sol, m2, coil II of relay X to negative battery. The coils I and II of relay X are diiferentially wound and on the closure of the circuit for coil II, the flux in the relay tends to reverse. The relay armature is repelled to normal and coil 11 is then short circuited by the negative battery on one side and a negative battery on the other side over contacts 202 and such of contacts (1.3, be, 04-, e l and g5, as may be operated, contacts Z1, cal and m2. At contacts $2 the circuit of Y is opened, also at :01 the condenser QA is disconnected from across the coil of relay Z and resistance YA and connected to the resistance YC through which resistance the condenser discharges. Contacts $3 open whereby any of the relays A--F at the time operated and relay G are released. On complete release the short circuit of coil II or" X is removed, so that relay X romperates from positive battery, resistance YD, contacts ll, sol, m2, coil II of relay X, contacts T2 to negative battery. Although contacts 93 are now open,

relay M is held operated over contacts m2, M;

and mi, since relay I-I remains operated in series with coil I of relay J when contacts g2 open. When contacts 92 restore the short circuit across coil I of relay J is removed and relay J operates in series with will of relay H. Operation of X starts the timing device (relays Y and Z) into operation for the purpose of timing the space that is taking place.

The space between marks should not exceed 1 /2 seconds, that is to say, the cycle recording relays AF which are set again into operation by closure of contacts $3 and g2 should not register the elapse of 1 seconds by the operation of relay E, before relay X is again released.

The space being assumed to be of permissible duration the cycle recording terminates due to the release of relay S on a fresh marking signal being received. This takes place by reason of relay then being operated. Contacts scl change over and connects in coil I of relay X, in place of coil II. The ux in the relay commences to fall is .led to normal by the eneroi its coil I, the re-operation of the relay evented by means of coil I being short in over i r red contacts 902 and conic. M, ed and g5 as may be operated as and the re before described. y the opening of contacts sa2 relay M released. The timing device, relays Y and a, is thrown out of action by the opening of contacts x1 and .132.

When the operated relays in the cycle recorder have all been restored to normal by the opening of contacts 933 the short circuit across coil I of relay X (via contact 002) is removed and the relay re-operates, the timing device and the cycle recorder thereupon being set into operation to time the second mark. In the sequence recording device at this stage, relays H and J are operated in the circuit positive battery, contacts b2, coil I of H, coil I of J, contacts hi and T1 to negative battery.

The operation of the cycle recorder are as described in connection with the first received mark up to the time that relay G operates and locks, which takes place after the elapse of 3 /2 seconds. When relay G operates contact g2 closes and a circuit is made for coil II of relay H from positive over contacts 722, coil II of H, contacts 9'1, g2, 1'1 to negative. Coil II of H exercises an opposing action to that of coil I with the result that the relay releases and relay J is held in the circuit positive coil II of J, contacts 7'1, 9'2, 1'1 negative, although contacts 2 and hl open. On the release of relay H relay K is operated over contacts 7'3, b3 and r1 and locks up to contacts 11 over contacts 701. Relay M is operated over contacts 93 as before.

The second mark ceases before 4%; seconds have elapsed: relay S re-operates and relay SA then releases. Relay X is repelled to normal by the change over of contact sol to normal. Any relays of set A-G operated, are released by con tacts x3 opening. On the release of relay G contacts 512 open, relay J is thereby released as the circuit of its holding coil II is out.

Complete restoration of the cycle recording relays A-G allows relay X to re-operate over contacts r2, m2, sol and Z1. Relay M is held over contacts 3&2, k2 and ml.

The second space is then timed by the Y, Z combination and is assumed again to be less than 1 seconds. The third mark is also timed in the same way as the first and after 3% seconds, relay G operates with the result that relay H is operated as in the case of the first mark. The mark ceases before 4 seconds elapse whereupon relay S re-operates, relays SA and X release. Relay G as well as other relays of set A-F then operated, release. By the release of relay G, relay J, the circuit of which was prepared by the closure of contacts hl, operates as the short circuiting con tacts g2 are now opened.

As contacts kl are closed a circuit is made for relay L from positive over the coil of L operated contacts 713, 9'3 and k1. Relay L operates and closes a circuit for an alarm bell AB at contacts Z2. By contact ll opening, any further operation of relay X is prevented. Contacts [3 change over and close a circuit for a starting magnet SM of a morse signal recorder and remove a short circuit from the marking magnet MM of the recorder. The recorder is provided in case after the alarm signal is given, a signal indicating the position of the calling ship is transmitted. Contact $1 in this case controls the marking of received dashes and dots.

Relay L when once operated remains operated until relay R is caused to operate. This may be done by means of the reset key BK. The operation of the key causes relay R to operate. The other relays at the time operated, are H, J, K, L and M: relays in the set A-G having been released by the opening of contact 933. On the operation of relay R relays H, J K and L release due to the opening of contacts rl. Contacts 1'2 disconnect coil II of relay X and relay M is released when contacts 714 and k2 open. The release of L stops the recording action contacts 33 change over. When key RK is restored, relay it releases and the whole apparatus is in a normal condition and ready for further use.

The operations taking place in the selecting paratus if the marks or spaces are not of permissible value will now be described.

If the apparatus is at normal and a mark comes in, relay S releases, relay SA operates, thereby operating relay X. Relay X starts up the timing device (relays Y and Z). At contacts 333 a circuit is prepared for the relays A-G.

On the termination of the mark, relay X is released and by opening of contacts r3 any relays of the set AG already operated, are released. Relay G only operates on the elapse of 3 seconds and operates relay H to signify that a mark which exceeds 3 seconds has been received. A mark of duration of less than 3 seconds is not recorded. Neither is relay M operated over contacts /3 and relay M causes the timing of the subsequent space. The result is that if a mark endures less than 3 seconds, the apparatus is restored at once to normal. Ordinary morse traffic would be dealt with in this manner.

If a jamming signal is r solved, that is to say, the received mark endures more than 4 seconds, the operation of the cycle recording device will have proceeded so far that relays G and C are both operated, which can be seen from inspection of Figs. 6, in the case when relay Y operates for the tenth time. A circuit is then made for relay R over contacts 03 and 4. The relay operates and locks itself at contacts r2 dependent on contacts g4. By contacts 11 operating, any of the relays H, J and K of the sequence switch recorder already operated are released.

Relay S remains operated whilst the jamming signal persists so that relays SA, X and G remain operated. Relays Y and Z continue to beat, exercising control on the cycle recorder, relays A-F.

If the jamming signal endures more than 7% seconds then on the expiration of 7 seconds, relay E is repelled to normal and a circuit is made over contacts r3, e1, f3, (relay F is operated) contacts r3 left hand normal contacts of key RK, buzzer BZ to battery. The circuit remains closed until relay F is released which takes place about a quarter of a second later. The buzzer BZ thus functions momentarily. Relay E is released and relay F is operated again when a further four seconds have elapsed and the buzzer is again operated if the signal still persists.

On the signal ceasing, S re-operates and thereby relays SA, X, G, M and any operated relays of the set A-F are released as will now be understood without further detailed description. The opening of contacts 94 open the circuit of relay R. Relay R is provided with a copper sleeve to delay release until all other relays are at normal. If a correct mark or marks has or have been received and a subsequent intervening space is too long, the following occurs. Relay M is operated each time a permissible mark is received by contacts g3 and is held during the following space period over back contacts sa2, 114 or k2, m1, whilst the space persists. The space is timed by the operation of relays Y, Z, and the cycle recorder relays A F. On the elapse of 1 seconds relay E operates for the first time signifying that the maximum allowable space has been exceeded. Relay E closes its contacts c3 and as relay SA is at the time released, a circuit is made for relay R over contacts m2, 724 or k2, m1 and c3.

Relay R operates, releasing at contacts 11 the operated relays of the sequence recorder. contacts 12 the circuit of relay X is opened so that the relays of the cycle recorder are released at contacts Relay M releases on the opening of contacts 714 or k2 as the case may be as also does relay R when relay G releases. Relay R releases slowly to allow complete return to normal of the other relays.

If a second received mark or a third mark is too short, that is to say, does not endure for 3 seconds, and assuming that the previous mark or marks were of permissible duration and relays H and J or J and K were operated as previously described, relays G and M are not operated by the time the mark ceases so that on the release of relay SA, a circuit is made for relay R from negative battery over contacts sail and 714, or

k2 and m1 coil of relay R to positive battery and relay R operates causing the immediate restoration of the apparatus to normal as previously described.

The apparatus if required may be adapted for transmitting an alarm signal. For this purpose the key AK, relay U and magnet (or relay) TM shown on the right of the drawing, are provided.

The key AK is a two-position key and when thrown upwardly, three mark signals are sent with the permissible intervening spaces and than sending ceases. Thrown downwardly permissible marks and spaces are sent until the key is released. The transmitting magnet or relay TM is arranged to operate on wireless transmitting apparatus in such a way that a mark signal is sent when the magnet (or relay) is operated.

f key AK is thrown, whether upwardly or downwardly a circuit is closed from negative battery over the key contacts, coil of relay U, contacts rd, Z4, relay SA to positive. The two relays are operated and at contact ill the circuit of magnet TM is closed for the sending of a mark signal. Relay SA on operation causes the operation of relay X as in mark reception and the timing and cycle recording devices are set into operation. After 3 seconds relay G operates but relay A has released just previously. After a further half second has elapsed relay A re-operates and relay U is now short-circulted over contacts 05 and U6. The sending of the mark signal ceases. Relay SA being still operated the timing device and cycle recorder continue in operation.

When 4 seconds from the start have elapsed,

Bil

vments of Figs. 5 and 7 may be noted here.

relay R (as in signal reception) is operated over contacts 03 and g4. At contacts r l the circuit of relay SA is opened.

It will be assumed that key AK has been thrown upwar ly. The release of relay SA results in release of relay X and the relay does not immediately re-operate as contacts T2 are operated. The operated relays of set AG are released by the opening of contacts 3:3 but relay H which operated previously by reason of the operation of G remains held, despite the opening of contacts 11, since there is holding circuit over the contacts of key K. Relay J operates on the opening of contacts g2. Relay B itself is released when relays C and C- have fallen back and on reclosure oi contacts r4 relays SA and U are reoperated. The position at the moment is that a e--second mark has been transmitted and a space of second has followed.

The operation described is repeated, a like mark and space being sent and a further mark of 4 seconds duration is sent. On the conclusion of such sending the condition is arrived at as in the reception of an alarm signal, that is to say, relay L is operated and by the opening of contacts Z4 relays SA and U are cut out of circuit. The restoration of key AK results in the restoration of all parts to normal. If the key AK is thrown downwardly, then there is no holding circuit for the relays HK when relay R operates so that both the cycle recorder and sequence recorder are restored to normal and operations re-cornmence again and again until the key AK is restored.

Fig. '7 shows selecting apparatus which through being slightly more complicated than that of Fig. 5 (which is illustrative of the main features of the invention) provides better safeguards against interference by signals which may occur whilst an alarm signal is being received. It provides a tolerance beyond the prescribed duration of marks in that a mark is accepted provided it exceeds about 3.3 seconds and does not exceed 5 seconds. This tolerance is obtained by reversing the function of the control contact g2 of the cycle recorder as will be seen later.

Certain major differences between the arrange- Relay SA in Fig. 5 was operated by closure of contacts of relay 8 when the latter released. In Fig. 7 relay SA is released when relay S releases by reason of a short circuit imposed by relay S. By reason of the short circuit, relay SA is made slow to release without affecting its quickness to opcrate. Relay SA accordingly is less likely to release fully when a short mark or dot is received and start the timing device unnecessarily.

The timing of the spaces in Fig. 7. is carried out by an independent unit comprising the relays M, N, O and P, when it is started into operation on the cessation of a permissible mark. These relays when started execute a cycle of operation in a period of 1 seconds or preferably about 1.? seconds to give a slight tolerance.

Relays V W, V and V are filament supplyv relays individual to the fourvalves or" a receiver diagrammatically indicated at RR. Release of relay due to failure of a filament or cessation of suppl results in the closure of one of the corresponding contacts U 1, 11 1, 11 1, o l, whereby the alarm relay L is operated.

The relay X of Fig. 5 does not appear in Fig. '7 as the space timing is not done with the assistance of the cycle recorder.

Relay S is in the anode circuit of the last valve V and normally operated. It releases on the receipt of a marking signal and re-operates when this ceases. Contact 31 is therefore normally open and relay SA is consequently op rated in a circuit over its coil 1, contacts wl, and guard resistance YC, Its contacts sa l maintain the condenser QA disconnects from across relay Z and connected in a discha path over resistance It will be seen by inspection of Figs. 5 and '7 that the timing device used in l is the same, but the choke designated ZC in place of W.

When a marking arrives relay S releases, and places its contacts and cont .cts Z3, a hort circuit relay SA. Relay 53A releases W1] and on release condenser QA is connected cross relay Z andresistance YA over contacts sol. Contacts in the released position close a circuit for relay Y, which circuit includes contacts 21. Relay Y operates and at contacts yl closes a circuit for relay Z from positive battery HT, resistance YA, coil of relay Z, the condenser QA being in parallel with this circuit over contact; choke to negative battery HT. At contacts 1 2 a circuit is closed for relay A from positive contacts 52, coil I of relay A, contacts bl, 1/2, e5, m2 to negative. Interaction of relays Y and Z takes place. The period of the cycle of interaction is assumed to have been adjusted to be one half second. Fig. 3 shows by a chart the time at which relays are operated and released and the chart is of similar character to that shown in 6. The circuit arrangements of the set of relays A to F is the same as in Fig. 5 with exception that the control circuit which includes contacts g2 also includes contacts e5 relay E and therefore the general operation of the circuit will be fully understood without further detailed description, only a general recital being On the first closure of contacts g2 relay A operates and relay 35 operates on the subsequent opening of contacts r2 in the manner similar to that previously described in connection with 5. Relay A is released on the second operation of relay Y, and relay C is consequently operated; relay D is operated on the second release of relay Y. On the fourth operation of relay Y relay A is released; the closure of back contacts cl result in the release of relay C and on con tacts cl closing, relay E is operated.

Contacts e5 which are in the circuit controlled by contacts g2 are changed overthus resulting in the opening of the previously described circuit for relay A. The immediate result of this, is that is connected to its front contact and thus to the back contact of contacts 112. Reference to Fig. 8 1

will make this clear, and in. particular, relay A will now be operated on the fourth release of relay Y and not on the fifth operation. There is actually a shift of the operation periods of the relays A and B by an amount equal to the release period of relay Y.

This relay A operates on the fourth release of relay Y and relay 13 operates on the fifth operation of that relay. On the fifth release of relay Y relay A releases and relay C operates from the start.

and on the sixth operation of relay Y relay B releases and relay D operates. On the sixth release of relay Y relay A re-operates followed by relay B on the seventh operation of relay Y. When relay Y releases for the seventh time relay A releases causing the release of relay C. Relay C on releasing causes the cnergization of coil II of relay E from positive contacts e2, coil II of relay E, contacts fl, (Z3, 01 and sa2 to negative. Relay E therefore releases and by the release of contacts e5 returning to normal the control exercised at the start by contacts 1 2 is restored. Furthermore the circuit made by released con tacts y2 is now broken on the restoration of contacts e5 with the result that relays B, D and F release in turn. On the release of relay E before relay F releases a circuit was made for relay G over contacts sa2, e1, r3, f3 and coil I of G. Relay G operates and locks up over its contacts 91 and contacts m2 before relay F is released, as before stated. Relay G at contacts g2 closes a circuit for relay H over its coil I in a circuit over contacts Ti, 1123, 92, 7'1, coil I of H, contacts 7'2. The circuit operations in the sequence recording relays H, J, K, is as described in connection with Fig. 5 and needs no further description.

Returning to the seventh release of relay Y, all the relays A to F become released as a result. Relay G having operated signifies that the received mark has endured suiilciently long. The next operation of relay Y results in the operation of relay A and the cycle recording or the interaction of relays Y and Z would proceed until relay Y operates for the tenth time, that is, five seconds However, as it is assumed that a permissible mark is being received, the interaction of relays Y and Z is stopped before five seconds have elapsed by the re-operatlon of relay S and re-operation of relay SA consequent on the opening of contacts s1.

When relay G operated, a circuit was prepared for relay M by the change over of contact g4 and the circuit was completed on the operation of contacts as. The circuit is from positive battery, over guard resistance YF, contacts m2 and g4 in parallel. coil of relay M, contacts h5 to negative. Relay M operates and opens contacts 1112 but relay N is still short-circuited over contacts 94.

When the mark signal being received, terminates, relay G is released by the opening of its locking circuit at contacts sa2.

Contacts 94 fall back, but as contacts ml are open relay M is not short circuited. Relay M at contacts m2 removes the short circuit across relay N which then operates in series with M. Relay N operating, makes a circuit for relay 0 including guard resistance YG by opening contacts n1 and on relay 0 operating, relay P is brought into circuit by the opening of contacts 01. Relay P operating short circuits relay M at contacts p1 and the relay releases after a short interval. It is then further short-circuited over contacts g4 and. m1 on the restoration of the latter. The release of M results in relay N being short-circuited at contacts m2 and in like fashion relays O and P are caused to release. From the time contacts g4 fall back, until the time relay P, after operation has been released, a period of just over 1 seconds intervenes.

It may be noted that an exceptionally long release lag of relays M, N, O, P, is obtained by the combined effect of a short circuit and the fact that the relays have a sleeve or a copper slug.

It is assumed that the space after the mark previously received, lasts less than 1 /2 seconds and the effect of a complete cycle of relays M-P Will be described later. The succeeding mark causes the same operation as for the first mark and when relay G re-operates relay H is released leaving relay J held over its coil II and contacts 9'1, 92, w3 and r1. Relay K is then operated in a circuit over contacts 7L3, i3, 103 and T1 and locks up in a circuit over its contacts kl to the said contacts 103 and T1. The release of relay G on the termination of the second mark starts relays M-P into cyclical operation and causes release of relay J by the opening of contacts 92.

A third permissible mark causes again the operations described for the first mark and on relay G operating relay H is re-operatecl. On the mark ceasing, relay J operates when contact 92 opens due to release of relay G. A circuit is now made for alarm relay L from positive battery over the coil of L, contacts as, 7'3, 7:1, 1013, r1 to negative. Relay L operates and closes at con tacts Z2 a circuit for the alarm bell AB. Contacts 13 open to prevent response of relay SA to further signals. Contacts ll open to prevent restoration due to the space being too long. Contacts Z2 also close a circuit for the start magnet SM of a recorder, if such be fitted, and contacts Z3 connect in the marking magnet MM so as to place this under control of contacts 31 of relay S to receive any further signals.

To re-set the apparatus, the re-set key RK is pressed whereby relay Q is operated over an obvious circuit. The closure of contacts 91 causes operation of relay R over its coils I and II. Relay R at contacts r1 opens the circuit of relays J, K and L and they release. The relays AG were released when the terminating space occurred by reason of the re-operation of relay SA. On the key RK being restored relays Q and R release in turn and the apparatus is at normal and ready for further use.

It may be noted here that when relay SA is operated at the end of a mark it is kept operated over its coil II until all the contatcs a3, b4, 04, c4, and g5 are at normal, thus ensuring that the set of relays A--G are positively released at contacts sa2.

Consideration will now be given to the operations in the apparatus if a non-permissible mark or space is received.

126 If a first mark is too short, relays S and SA re-operate before relay G operates. No record of the mark is therefore made in the sequence recorder-relays H--K and relays Y and Z are set out of action and any relays in the set A-F released when relay SA re-operates.

If a mark signal exceeds 4 seconds plus the tolerance i. e. 5 seconds in total, relay Y operates for the eleventh time and for the first time relays E and G are both in the operated condition.

A circuit is therefore made over contacts g3, e3 and coils I and II of relay R. The relay operates and contacts r2 and r4 close a circuit for holding the relay dependent on contacts 93 alone. At contacts 1'1 relay H is released.

Relay S and therefore SA remain released whilst the jamming signal persists and relay G remains operated and furthermore relays Y and Z interact so long as the signal persists.

On the expiration of about seven seconds relay Relay A releases, half a second later opening the buzzer circuit and after a further half second has elapsed, relay A re-operates and the buzzer BZ again operates and for a period of half a second. When relay E operates again, the buzzer circuit is opened at contacts e1. The buzzer gives two short signals during release periods of relay E so long as the signal persists. On cessation of the signal, relay SA re-operates and all relays operated in set A-G are released and relay R releases on the opening of contacts g3.

If an intervening space is too long the following occurs. Relays M, N, O and P are set into action when the space starts and operate once and release in succession. As a mark has already been recorded, either relay H or relay K is operated. The space being too long, relay SA will not have released by the time a cycle of the relays M, N, O, P has been completed. A circuit is therefore made for relay R from negative battery over operated contacts m3, contacts Z1, m3, p2, k4 and/or 102, coils I and II of relay R to positive. Contact 1'1 releases the sequence recorder when R operates. The relays A-G were previously released. Contact r4 closes to delay release of Relay R when contacts M and 702 open to ensure complete release of relays H and K.

It may be noted that contact m3 prevents operation of R when relay SA operates at the termination of a permissible mark.

As aforementioned when an actual alarm signal is received relay SA releases when the mark subsequent to a correct space is received so that the circuit of R cannot be made at contacts sa3.

At this time relay R will be operated and the circuit for R will be prepared over contacts sa3, Z1, p2, R12 and coils I and II of relay R. Therefore if a mark terminates prematurely, that is, relay G does not operate and allows the operation of j relay M indicating that the minimum permissible period for a mark has expired, relay SA will fall back and complete the above traced circuit for relay R at contacts sa3. Relay R will cause the. release of the cycle recording device as previously described.

To transmit an alarm signal, the switch TS is closed to energize relay W. Relay W operates and at contacts wl removes relay SA from control by relay S. Contacts w2 remove relay L from the control ofv the filament supply relays 12 etc. The selecting apparatus is. thus disassociated from the signal receiver and not subject to interference from the receiver.

Contacts 103 prevent the sequence recording relays operating. At contacts 104 and over the contacts 96 and 03 in parallel the relay TC which controls the transmission of marks by wireless sending apparatus is energized and a mark signal is sent out.

By the release of relay SA at contacts wl, the interaction of relays Y and Z is started as also cycle recording, just as if a mark were being received. On the ninth operation of relay Y (four seconds having elapsed) contact 112 closes and relay C is operated. Relay G is already operated. by this time so that the circuit of relay TC is interrupted by both contacts g6 and 03 being opened. A space in the signal sending therefore ensues. On relay Y operating for the eleventh time, relay C releases and brings about operation of relay E. A circuit is now made over contacts g3 and c3 for relay R. The release of relay C results in re-closure of the circuit of the trans mitting control relay TC, and relay R on operation at contacts 15 makes acircuit for relaySA over its coil I and contacts wl. The operation of relay SA causes release of relays Y, Z and any relays operated in set AG. On the release of relay G, the circuit of relay R is opened at contacts g3. Relay it releases and releases SA at contacts r5 so that the operation described is repeated. The sequence of four second marks and. one second spaces continue until switch TS is' restored. In connection with signal reception it may be mentioned that although relay L is operated when a filament in the receiver fails and gives the bell alarm signal, yet it can be established that the signal is not due to an actual alarm signal having been received since on then pressing re-set key RK, the relay L will not be released as in the case, of an actual alarm signal, as in the lattercase the operation of key AK causes relay Q to operate and operate relay R which at contacts 1'1 disconnects the holding circuit for the relays H, J and K which relays at their contacts n3, 7'3, and k3 control the circuit of relay L as previously de-- scribed. r

Fig. 9 shows a further selecting apparatus. Compared with the apparatus of Fig. '7, the general working method is the same and as previously fully described with one difference that relay SA is not short-circuited on release of relay S but is caused to operate on the release of relay S over contacts s1, Z3, and resistance YC. In that respect the arrangement is similar to Fig. 5. The purpose of short-circuiting relay SA in Fig. '7 to cause release was to render the working of the apparatus less liable to interference by short marks'such as morse signals and to prevent unnecessary starting up of the timing and cycle recording devices. The relay SA is normally energized and its current consumption may be objected to.

In Fig. 9 the same object is achieved by arranging that relay Z is the first to operate on the reception of a mark. It will be remembered that relay Z does not operate until the condenser shunting it has charged up to the operating voltage of Z. In the case of a short mark, contacts sal may restore before relay Z operates.

j Corresponding contact alterations have been made namely relay Y is now controlled by a make contact of relay Z and relay Z by a break contact of relay Y. When a mark is received relay S releases as before described and the following circuit for relay SA is closed, positive contacts 81, Z3, coil of relay SA, resistance YC to negative, and at contacts sal performs the folowing circuit operations (a) disconnects the resistance YB from across the condenser QR (b) connects the condenser QR across relay Z and resistance YA, (c) closes the following circuit for relay Z from positive battery HT, resistance YA, coil of relay Z, contacts sal, yl, choke ZC, to negative battery HT. At contacts $112 the negatve battery for holding the relays AF is connected up, and at contacts'sa3 the negative battery for the operation of relay R when an intervening space is too long is disconnected as before described in connection with Fig.7. Contacts sa4 open a possible short circuit across relay SA prepared to be applied when any one of the relays A, B, C, E or G, operate their respective contacts a3, b4, '04, e4, 95, which circuit arrangement is provided so that when relay SA falls at the end of a permissible mark it is short circuited over any operated cheer the said" contacts and the contacts salj It will also be noted that in contrast with Fig. 7 150 there are no contacts of relay E-in series with contacts 3/2.

The originating circuit for relay G is now controlled by contacts a5, 03 and f3 the operation of this relay being substantially the same as the relay G in Fig. 7. In the holding circuit for relay G is an additional relay GA which when relay F operates is short-circuited by contacts 74. When relay F is subsequently released relay GA operates and contacts gal opening prevent release when relay F again operates.

The circuit for operating relay R if a mark exceeds the prescribed duration includes contacts 9112 and 05.

It is thought that a full description of the working is unnecessary in view of the similarity of the previously described example. As in the Fig. '7 arrangement, relay G controls the relays H, J, K to record permissible marks. Relays M, N, O, P time intervening spaces and cause operation of relay R if a space is too long or if a permissible space has ensued and the following mark is too short.

The periods at which relays A-F operate are as shown by the chart of Fig. 6. Relay G of Fig. 9

operates when contacts a5, c3 and f3 are closed, which as the chart shows, is after the elapse of three seconds from the setting into operation of relay Y. Actually it is somewhat more than three seconds after the mark commences, the amount depending on the release lag of relay S and the operating lags of relays SA and Z, but is still less than 3 seconds. Relay GA operates the first time relay F releases after relay G has been operated, namely, on the eighth release of relay Y. Relay GA having operated, a circuit for relay R is made when relay C reoperates, which takes place on the tenth operation of relay Y, that is after the expiry of 4%,; seconds plus the lags referred to. i

If it is desired to delay the time at which relay R operates, contacts of relay D or E or F may be used in place of the contacts 05.

The selecting apparatus has been herein described as particularly suitable for marine wireless alarm signals, but of course, is capable of dealing with any other signal having prescribed marks and spaces.

As regards the sending of a signal, this may be caused to take place automatically on the occurrence of certain events, for example, outbreak of fire.

The intermittent operation of the buzzer BZ when a jamming signal is received indicates to the operator that the selector is held by a jamming signal and therefore is held against the reception of aregular or a distress signal. To release the apparatus switch TS could be thrown temporary operating relay W over an obvious circuit. At

contacts 1.01 a circuit is closed from positive coil I ofrelay SA, contacts 101 and T5 to negative. Relay SA would operate and at contacts sa2 release relay G, which is locked over its coil II and contacts 91, and also release any of the relays A-F in the cycle recorder that may be operated. The release of relay G would release relay R as the locking circuit for this relay over contacts g, r and 1 would be broken at the former contact.

If the jamming signal still persists after the restoration of switch TS the wholecycle of operations would be repeated until the buzzer BZ again intermittently operated.

What I claim as my invention and desire to secure by Letters Patent is:

1. Selective apparatus adapted to respond to signals consisting of a sequence of marks and intervening spaces of prescribed duration comprising a signal receiving means, a timing device for periodically opening and closing a circuit and having an energizing circuit to control its operation, control contacts controlled by the signal receiving means operative to close the energizing circuitof said timing device during the reception of a mark, a cycle recording means for recording the number of cycles of operation of said timing device during the reception oi a mark and controlled by the periodic circuit of the timing device, a sequence recording device operated each time when the cycle recording device has ascertained that the timing device has been in operation for a period corresponding to the minimum prescribed period for a mark, releasing means whereby the cycle recording device causes restoration of the sequence recording device to its unoperated condition if a mark endures beyond the prescribed amount, control means associated with the sequence recording device operative to close an alarm circuit when a prescribed succession of marks of allowable duration have been received, means for determining whether a space intervening between marks exceeds the allowable duration, a signal transmitting device, manually controlled means for disassociating the said signal receiving means from the timing device and operatively associating the signal transmitting device with the apparatus to transmit a signal, means for starting the timing device simultaneously with the transmitting device in the sending of a mark signal, means under the control of the cycle recording device for stopping the transmitting device after the cycle recording device is in an operative condition corresponding to the reception of a prescribed mark, and means for subsequently stopping the operation of the timing device and consequently the cycle recording device after the elapse of a period corresponding to a permissible space and causing restoration thereof to normalwith subsequent re-starting.

2. Selective apparatus adapted to respond to signals consisting of a sequence of marks and intervening spaces of prescribed duration comprising a signal receiving means, a timing device for periodically opening and closing a circuit and having an energizing circuit to control its operation, control contacts controlled by the signal receiving means operative to close the energizing circuit of said timing device during the reception of a mark, a cycle recording means for recording the number of cycles of operation of said timing device during the reception of a mark and controlled by the periodic circuit of the timing device, a sequence recording device operated each time when the cycle recording device has ascertained that the timing device has been in operation for a period corresponding to the minimum prescribed period for a mark, releasing means whereby the cycle recording device causes restoration of the sequence recording device to its unoperated condition if a mark endures beyond the prescribed amount, control means associated with the sequence recording device operative to close an alarm circuit when a prescribed succession of marks of allowable duration have been received, means for determining whether a space intervening between marks exceeds the allowable duration, a signal transmitting device comprising a transmitting relay with apparatus to transmit a signal, a manually operated switch, a control relay. controlled by said switch, contacts of said control relay which when the relay is in an operated condition close a circuit for the transmitting relay and prevent the signal receiving means from controlling the timing device, said contacts starting the timing device into operation, means in the cycle recording device situated in the circuit of the transmitting relay and operating to open said circuit on the expiration of a period corresponding to a prescribed permissible mark, terminating means whereby the releasing means operating on signal reception upon a mark exceeding the allowable duration controls jointly with said control relay a circuit for terminating the operation of the timing device and cycle recording device and restores same to the non-operating condition, the said terminating means ceasing to operate on said devices being restored.

3. Selective apparatus adapted to respond to signals consisting of a sequence of marks and intervening spaces of prescribed duration com= prising a signal receiving means, a'timing device for periodically opening and closing a circuit and having an energizing circuit to control its operation, control contacts controlled by the signal receiving means operative to close the energizing circuit of said timing device during the reception of a mark, a cycle recording means for recording the number of cycles of opreation of said timing device during the reception of a mark and controlled by the periodic circuit of the timing device, a sequence recording device operated each time when the cycle recording device has ascertained that the timing device has been in operation for a period corresponding to the minimum prescribed period for a mark, releasing means whereby the cycle recording device causes restoration of the sequence recording device to its unoperated condition if a mark endures beyond the prescribed amount, control means associated with the sequence recording device operative to close an alarm circuit when a prescribed succession of marks of allowable duration have been received, means for determining whether a space intervening between marks exceeds the allowable duration, and means operative to give a periodic signal during such time as elapses after the permissible prescribed duration of a mark has been reached.

4. Selective apparatus according to claim 3, wherein the means operative to give a periodic signal comprises a relay, a circuit therefor controlled by contacts associated with the cycle recording device and operated when a mark has exceeded the permissible value, a locking circuit for said relay, such locking circuit being kept closed so long as the mark continues, a signal circuit, contacts therein closed when said relay operates, and further contacts therein which under the control of the cycle recording device are periodically closed and opened whilst the mark continues.

HORACE EDGAR HUMPHRIES. 

